[RFC] Iteration tools

Hello Ionut,

some remarks about your proposal:

1. You can turn any array into a Traversable using
   (Recursive)ArrayIterator. Though this solution is still slow. The issue is
   that the c-level code needs to verify the current pointer every single time
   it uses it and that means traversing the array from the beginning. That
   said we might want to:
   a) Optimize that for cases where we don't have to. Basically when nothing
   else is pointing to the array (refcount==1) we know when the array can be
   changed and do not have to verify it always.
   b) provide a lower level array to traversable mechanism that operates on
   the current pointer provided by the array itself. That way having no need
   to verify that pointer at all.

2. Ther are iterator_apply(), iterator_to_array(), iterator_count()
   The first can be used for a lot of the things you were looking for,
   especially when used together with lambdas. Also not that you can use it to
   pass the iterator itself to the function being called easily.

Still a few of the things you mention can be implemented faster in the same
way iterator_apply() was done. In fact the code can be based on the lovel
c-implementation provided.

marcus

Monday, November 3, 2008, 4:07:14 PM, you wrote:

Hello everybody,

As a result of the advice given in the thread "array_key_exists BC
break", I have written an
RFC concerning some higher order functions that, I believe, could a
helpful addition to the language.

Please note that I'm a userland developer and have no clue about PHP
internals so please
forgive any stupidities I might have said in the RFC and make the
appropriate corrections.
That also means that, if positive feedback is received, this RFC needs a
developer with PHP
internals knowledge to implement it.

The RFC can be found here: http://wiki.php.net/rfc/iteration-tools

Hoping that I've made sense in what I wrote there, please feel free to
comment as you like.

Regards,
Ionut

Best regards,
Marcus

Hi Marcus,

Thanks for your answer.

I had no idea there is an iterator_apply() function, I did a little bit
of search after you mentioned it
and found it nowhere in the docs but apparently it is present in my
5.2.6 installation. iterator_to_array()
and interator_count() are very useful functions which I had knowledge of
but forgot about them in my wiki.

I recognize that my proposal can easily be implemented in userland code
with the classes and functions
that we already have, as you mentioned already. The only real advantage
is the speed given by the C level
code and a common, standard API for array and Traversables. This way
array_map(), array_reduce() and
the like could be deprecated. I always have to look in the docs or pay a
little attention to my IDE to see
what param goes where.

Anyway, I see there's nobody else that would like this but it's ok, at
least now we have namespaces so that
I don't have to come up with ugly names like my_map() for these kind of
helper functions.

Cheers,
Ionut

Am 03.11.2008 um 16:41 schrieb Marcus Boerger:

2. Ther are iterator_apply()

owww that sounds like it really needs docs :